基于CT三维重建与逆向工程技术的煤体数字模型的建立

为了建立能够表征煤体真实孔隙结构的数字模型，进而进行数值模拟研究，通过μCT225kVFCB高精度CT系统扫描得到了大柳塔煤矿长焰煤CT数据，可观测到的最小孔隙直径为1.94 μm。使用基于Matlab语言的三维重建程序结合逆向工程技术，提出了一种将煤体CT三维数据转换为CAD数字模型的方法。以Ansys建立的煤体有限元模型为例，对煤体瓦斯渗流进行了模拟，分析了煤体孔隙内的速度及压力分布规律，并计算了沿X、Y、Z方向的渗透系数。计算结果表明：在微观尺度下（< 100 μm）煤体渗透系数呈现各向异性，其受煤体结构的影响较明显。提出的基于CT三维重建结合逆向工程技术构建的煤体CAD数字模型不仅可进行有限元分析，同时也可以被EDEM等离散元分析软件所使用，拓宽了煤体CT三维数据的应用范围，丰富了煤体在微观尺度上的研究方法。

Establishment of digital coal model using computed tomography based on reverse engineering technology and three-dimensional reconstruction

The aim of this paper is to establish a digital model for characterizing the actual pore structure of coal and further simulating the gas seepage in coal. The computed tomography (CT) data of long-flame coal samples from Daliuta coalmine is obtained through the μCT225kVFCB high precision CT system. It is found that the minimum pore diameter in coal sample is 1.94 μm. Meanwhile, a new method is developed to convert CT three-dimensional (3D) data into CAD digital model, according to the reverse engineering technology and a Matlab language based 3D reconstruction program. As an example, a finite element model is established by Ansys software to simulate the gas seepage. Then the distributions of gas velocity and pressure in the coal pores are analyzed and hydraulic conductivities along X, Y and Z directions are also calculated. The results indicate that the permeability of coal exhibits anisotropy at microscale (<100 μm) and is greatly affected by coal structure. The newly developed CAD digital coal model can be used not only for finite element analysis, but also for discrete element analysis such as EDEM software. Therefore, this study broadens the application of 3D CT data and extends research areas of coal at microscale.